One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | A | Only Denon CEOL RCD-N12 has AirPlay 2 and HEOS. |
| Room to grow | A | Only Denon CEOL RCD-N12 offers a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Built-in sources | depends | Denon CEOL RCD-N12 has a CD player built in. That is one less box if you still play discs or listen to radio, and dead weight if you do not. |
| Amplifier class | depends | Denon CEOL RCD-N12 is Class D and Arcam A5 is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Denon CEOL RCD-N12 takes up about 43% less shelf area (901cm² against 1580cm²), and it is 43mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
A Denon CEOL RCD-N12 B Arcam A5
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Denon CEOL RCD-N12 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.